A plasma display panel (herein after referred to as a PDP) can achieve higher definition and have a larger screen. Thus, a television screen using a PDP approx. 65 inch in diagonal is commercially available.
A PDP is basically made of a front panel and a rear panel. The front panel includes a glass substrate made of sodium borosilicate glass by the float method, display electrodes that are made of stripe-like transparent electrodes and bus electrodes formed on the principle surface of the glass substrate on one side thereof, a dielectric layer covering the display electrodes and working as a capacitor, and a protective layer that is made of magnesium oxide (MgO) formed on the dielectric layer. On the other hand, the rear panel is made of a glass substrate, stripe-like address electrodes formed on the principle surface of the glass substrate on one side thereof, a primary dielectric layer covering the address electrodes, barrier ribs formed on the primary dielectric layer, and phosphor layers formed between the respective barrier ribs and emitting light in red, green, or blue.
The front panel and rear panel are hermetically sealed with the electrode-forming sides thereof faced with each other. A Ne—Xe discharge gas is charged in the discharge space partitioned by the barrier ribs, at a pressure ranging from 400 to 600 Torr. For a PDP, selective application of image signal voltage to the display electrodes makes the electrodes discharge. Then, the ultraviolet light generated by the discharge excites the respective phosphor layers so that they emit light in red, green, or blue to display color images.
Silver electrodes are used for the bus electrodes in the display electrodes to ensure electrical conductivity thereof. Low-melting glass essentially consisting of lead oxide is used for the dielectric layer. The examples of a lead-free dielectric layer addressing recent environmental issues are disclosed in Japanese Patent Unexamined Publication Nos. 2003-128430, 2002-053342, 2001-048577, and H09-050769. Further, an example of using binding glass that contains bismuth oxide and has a low softening point for the primary dielectric layer covering the address electrodes is disclosed in Japanese Patent Unexamined Publication No. H10-275564.
Because a PDP can achieve higher definition and have a larger screen, a television screen using a PDP approx. 65 inch in diagonal is commercially available. Recently, with advancement of application of PDPs to high definition televisions having scanning lines at least twice as many as conventional televisions compliant with the National Television System Committee (NTSC) system, PDPs containing no lead to address environmental issues have been required.
However, such compliance of a PDP with high definition increases the numbers of scanning lines and display electrodes, and decreases the spacing between the display electrodes. These changes decrease the pitch and width of the barrier ribs of the rear panel. Thus, defective shapes of the barrier ribs are likely to occur, and affect the display quality.